Abstract <p>In response to environmental changes, Mediterranean forests are subjected to multiple selective pressures, potentially leading to phenotypic plasticity and local adaptation. We examined the intraspecific variability in photosynthetic leaf traits of seven Tunisian provenances of cork oak (<i>Quercus suber</i> L.<i>)</i> sourced from contrasting environmental conditions. The provenances included ʻKef Errand’ (KER), ʻSidi Zidʼ (SZD), ‘Djebel Essarej’ (JES), and ʻDjebel Chehid’ (JCH) from drier sites, and ʻMejen Essef’ (MEJ), ʻBellif’ (BEL), and ‘Feidja’ (FEJ) from wetter sites. Significant variation was recorded in net CO₂ assimilation (<i>A</i>_n) and stomatal conductance (<i>g</i>_s), where the highest and lowest values were recorded in MEJ and JES provenances respectively.CO₂ response curves revealed that photosynthesis rates at saturated CO₂ (<i>A</i>_sat) were highest in SZD and lowest in JES, while no differences were observed in relative stomatal limitation (<i>L</i>_s) across the provenances. The maximum rate of carboxylation, <i>V</i>_cmax, ranged from 63 µmol/(m² s) for JES provenance to 82 µmol/(m² s) for MEJ provenance, meanwhile the maximum rate of electron transport, <i>J</i>_max, ranged from 119 µmol/(m² s) for JES provenance to 155 µmol/(m² s) for MEJ provenance. A strong positive correlation was found between net CO₂ assimilation (<i>A</i>_n) and both stomatal conductance <i>g</i>_s (<i>r</i> = 0.88) and <i>V</i>_cmax (<i>r</i> = 0.84). In contrast, <i>A</i>_n showed a significant negative correlation with the CO₂ compensation point (Γ, <i>r</i> = −0.83). These results suggest that provenance-specific differences in CO₂ uptake are related to varying capacities for the biochemical reactions that regulate the gas-exchange process. This study reveals a potential association between geographic origin and photosynthetic efficiency, informing future selection of resilient cork oak for reforestation efforts.</p>